[Clinical effect of umbilical cord blood transplantation in 37 pediatric patients with hematologic malignancies: a single-center experience].

OBJECTIVE: To evaluate the clinical effect of umbilical cord blood transplantation (UCBT) in children with hematologic malignancies. METHODS: A retrospective analysis was performed on the clinical data of 37 pediatric patients with hematologic malignancies that consisted of 14 cases of acute lymphocyte leukemia, 9 cases of acute myeloid leukemia, 5 cases of juvenile myelomonocytic leukemia, 3 cases of chronic myeloid leukemia, 2 cases of acute mixed leukemia, 3 cases of myelodysplastic syndrome, and 1 case of lymphosarcomatous leukemia. Thirty-seven children with hematologic malignancies received UCBT from unrelated donors (34 cases) and related donors (3 cases). Grafts were 6/6 HLA-matched in 5 cases, 5/6 HLA-matched in 12 cases, 4/6 HLA-matched in 11 cases, and 3/6 HLA-matched in 9 cases. Before transplantation, these patients received rabbit antithymocyte globulin-containing conditioning regimen. The myeloablative conditioning regimen was given in 36 cases and the reduced-intensity conditioning regimen in one case. The median age of transplantation was 5.7 years, and the median weight was 20 kg. The grafts that contained a median of 6.2×10(7) total nucleated cells (TNC)/kg and 2.7×10(5) CD34(+) cells/kg were infused. RESULTS: The median times to neutrophil engraftment and platelet engraftment were 12 days and 25 days, respectively, and the rates of neutrophil engraftment and platelet engraftment were 95% and 78%, respectively. The rate of neutrophil engraftment was positively correlated with the number of CD34(+) cells (P=0.011), while the rate of platelet engraftment was correlated with the numbers of CD34(+) cells and TNC (P=0.001; P=0.014). The incidence rates of acute and chronic graft-versus-host disease were 49% and 11%, respectively. The median follow-up was 54 months. The 5-year transplant-related mortality, overall survival, and disease-free survival were 27%, 57.4% and 41%, respectively. CONCLUSIONS: UCBT is an alternative source of hematopoietic stem cells for patients with hematologic malignancies.